A shift is a simultaneous change of position or stance by two or more offensive players after the ball is ready for play before the snap for a scrimmage down (A.R. 7-1-3-I-II and A.R. 7-1-2-I-IV).
The shift ends when all players have been motionless for one full second.
The shift continues if one or more players are in motion before the end of the one second interval.